Late-summer heat wave grips Southern California, prompts smog warnings

A man jogs along the coast in San Clemente, Calif., on Wednesday, Sept. 4, 2024, as much of Orange County and Inland areas were under an excessive heat warning. A heat wave is pushing temperatures into triple digits in many areas in Southern California. (Paul Bersebach/The Orange County Register via AP)

LOS ANGELES – Temperatures were on the rise across the Southland Wednesday as a late-summer heat wave settled over the region, with sweltering conditions expected to continue into the weekend.

“Models continue to advertise a dangerous heat wave across Southern California and much of the West Coast through the weekend as strong high pressure aloft combines with very weak offshore flow at the surface,”according to the National Weather Service.

Forecasters said it will be “very hot through the weekend, hottest Friday and Saturday.”

Maximum temperatures are expected to gradually increase each day this week. Even traditionally cooler areas along coast will see temperatures 3 to 6 degrees above normal.

An excessive heat warning took effect Tuesday morning in the western San Fernando Valley, and it will remain in force until 8 p.m. Saturday — one day longer than originally anticipated. Forecasters said the area could see temperatures reaching as high as 118 degrees.

An excessive heat warning was also in effect through 8 p.m. Saturday in the Santa Clarita Valley, the inland coastal areas stretching into downtown Los Angeles, the Santa Monica Mountains Recreational Area, Calabasas, eastern San Fernando Valley, San Gabriel Mountains, San Gabriel Valley, the Antelope Valley and Antelope Valley foothills and the 5 and 14 Freeway corridors.

Forecasters said those areas could reach 110 degrees.

The Santa Ana Mountains and foothills and Orange County inland areas were also under excessive heat warnings, with temperatures predicted up to 105 degrees.

Even coastal areas will not be immune from the heat. An excessive heat warning will take effect at 11 a.m. Thursday and remain in place until 8 p.m. Saturday for the Malibu Coast and Los Angeles County beaches, along with the Palos Verdes Hills, with some of those areas possibly reaching triple-digits, according to the NWS.

A less severe heat advisory will be in place for Orange County coastal areas from 11 a.m. Thursday through 8 p.m. Friday. Temperatures there are anticipated as high as 95 degrees.

“The hottest days with this event are expected to be Friday and Saturday in most areas, and of those two days Friday has the slight edge of being the peak day,” according to the NWS. “Overnight night lows will be warming up as well, especially in the foothills and lower mountain locations where some areas may stay in the 90s much of the night. Not quite as hot overnight for coast and valleys, but even there some warmer valley areas will stay above 80 until well into the overnight hours.”

A cooling trend is expected to begin by Saturday, slowly lowering temperatures over the ensuing days, reaching normal levels by about Wednesday of next week, according to the  NWS.

Due to the high heat, the South Coast Air Quality Management District issued an ozone advisory that will be in place until 8 p.m. Friday due to anticipated elevated smog levels because of the heat wave. The ozone level is expected to reach the unhealthy level or worse in the Santa Clarita Valley and portions of the San Gabriel Valley through Friday, according to the AQMD.

Officials warned the public to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun and check up on relatives and neighbors.

Residents were also urged to never leave children or pets in unattended vehicles, which can reach lethal temperatures in a matter of minutes.

The hot, dry weather will also create elevated fire conditions across the mountains, valleys and deserts throughout the week. (CNS)

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